Epoxy Resin Removal via Cooling and Peel-Back Angle
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Solution Overview
Problem
Existing methods for removing epoxy resin from a backing sheet either leave residue or degrade the resin due to heating or inefficiencies, which reduces the resin's effective life and complicates the transportation and usage in aerospace applications like SQRTM.
Innovation Solution
A method and apparatus that cool the epoxy resin to a temperature below its glass transition temperature and use a controlled peel-back angle to separate it from the backing sheet, allowing for efficient removal without heating, utilizing cold gases or liquefied gases for cooling and a vacuum for collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the epoxy resin is heated to remove it from the backing sheet, then the resin can be removed more easily, but the resin degrades and its effective life is reduced
Solution Approach 1:
The patent changes the temperature parameter from elevated (heating) to reduced (cooling below glass transition temperature). This parameter change fundamentally alters the resin's physical state and removal mechanism, allowing removal through brittleness rather than thermal softening, thereby avoiding degradation while maintaining ease of removal
Solution Approach 2:
Instead of heating the resin to make it removable (conventional approach), the patent inverts the approach by cooling the resin below its glass transition temperature to make it brittle and removable. This inversion of the temperature approach resolves the contradiction between ease of removal and resin preservation
2Ease of operation
If the epoxy resin is stored at room temperature, then it is more convenient for handling, but it reacts prematurely and sets in feed passages
Solution Approach 1:
The patent applies preliminary cooling action to the resin below its glass transition temperature before removal and storage. This preliminary temperature reduction prevents premature reaction during subsequent handling and storage, allowing the resin to be stored in a stable state without requiring continuous refrigeration at -18°C
Solution Approach 2:
The patent changes the storage temperature parameter from room temperature (which causes premature reaction) to below glass transition temperature (which provides stability). This parameter change enables the resin to be handled conveniently while maintaining stability, resolving the contradiction between ease of operation and resin reliability
3Productivity
If a shearing device is used to remove resin from the backing sheet, then protruding portions can be removed, but resin residue remains on the coated film
Solution Approach 1:
The patent changes the temperature parameter to below the glass transition temperature, which fundamentally changes the resin's mechanical properties from viscoelastic to brittle. This parameter change enables complete removal without residue, as the brittle resin breaks cleanly rather than adhering to the backing sheet, resolving the contradiction between removal efficiency and residue prevention
Solution Approach 2:
The patent creates a clean separation where the brittle resin breaks away completely from the backing sheet, leaving no residue. This complete separation effect is analogous to creating a perfect copy or replica of the original clean state, ensuring no material is left behind on the backing sheet for reuse
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the effective and efficient removal of epoxy resin from the backing sheet without degrading it, preserving the resin's life and facilitating its reuse in aerospace applications like SQRTM by maintaining the resin's brittleness and preventing premature reaction.
Implementation Method 1
adjusting the temperature of the epoxy resin to be at a temperature below the glass transition temperature of the epoxy resin
Data Source
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AI summary
Described herein is an apparatus and a method for removing an epoxy resin from a backing sheet at a temperature at or below the glass transition temperature of the epoxy resin. The apparatus (200) comprises a housing (210) in which is mounted a dispensing roll (220) comprising epoxy resin (230) on a backing sheet (240), a wind-up roll (250) comprising the backing sheet (240), a release element (260) over which the backing sheet (240) is directed, and a collection tray (270) for collecting pieces of resin (230a) removed from the backing sheet (240). The dispensing and wind-up rolls (220, 250) are mounted on respective drive shafts (225, 255) which are driven by a drive mechanism (285) controlled by a controller (280). A temperature controller (290) is also provided for controlling the temperature within the housing (210) so that it remains below or at the glass transition temperature of the epoxy resin. Angle (αa) is chosen to optimise the peel-back angle of the backing sheet (240) after is passes over the release element (260) in relation to the relative spacing between the dispensing and wind-up rolls (220, 250) and the release element (260).